lhcf: a lhc detector for astroparticle...

Alessia TricomiAlessia TricomiUniversity and INFN CataniaUniversity and INFN Catania

on behalf of the on behalf of the LHCfLHCf CollaborationCollaboration

LHCfLHCf: a LHC Detector for : a LHC Detector for AstroparticleAstroparticlePhysicsPhysics

EDS07 EDS07 -- 12th International Conference on Elastic 12th International Conference on Elastic and Diffractive Scattering and Diffractive Scattering -- Forward Physics and Forward Physics and

QCDQCDHamburg 21 Hamburg 21 –– 25 May, 200725 May, 2007

Alessia Tricomi Alessia Tricomi University & INFN University & INFN

The LHCf experiment at LHC The LHCf experiment at LHC EDS07, Hamburg 21EDS07, Hamburg 21--25 May 200725 May 2007

The The LHCfLHCf CollaborationCollaboration

ITALYITALYFirenze University and INFN:Firenze University and INFN:O.AdrianiO.Adriani,, ,, L.BonechiL.Bonechi, , M.BongiM.Bongi, , G.CastelliniG.Castellini, , R.DR.D’’AlessandroAlessandro, , P.PapiniP.PapiniCatania University and INFN:Catania University and INFN:A.TricomiA.Tricomi

JAPAN:JAPAN:STE Laboratory Nagoya University:STE Laboratory Nagoya University:Y.ItowY.Itow, , T.MaseT.Mase, , K.Masuda,Y.MatsubaraK.Masuda,Y.Matsubara, , H.Matsumoto,H.Menjo,T.Sako,HH.Matsumoto,H.Menjo,T.Sako,H. . WatanabeWatanabeWasedaWaseda University:University: K. K. KasaharaKasahara, , Y.ShimizuY.Shimizu, , S.ToriiS.ToriiKonan University:Konan University: Y.MurakiY.MurakiKanagawa University Yokohama: Kanagawa University Yokohama: T.TamuraT.Tamura

SPAINSPAINIFIC Valencia:IFIC Valencia:A.FaussA.Fauss, , J.VelascoJ.Velasco

FRANCEFRANCEEcoleEcole PolitechniquePolitechnique Paris:Paris:M. M. HaguenauerHaguenauer

USAUSALBNL Berkeley:LBNL Berkeley:W. TurnerW. Turner

CERNCERND.MacinaD.Macina, A.L. Perrot, A.L. Perrot



OutlineOutlineIntroductionIntroduction–– Main problems in HECR physics: GZK cut off, Main problems in HECR physics: GZK cut off,

chemical compositionchemical compositionIdea of Idea of LHCfLHCf–– Measurement of neutral particles emitted into Measurement of neutral particles emitted into

very forward at LHCvery forward at LHCSimulation and test beam resultsSimulation and test beam results–– Calibration of MC code Calibration of MC code Conclusions, plans and scheduleConclusions, plans and schedule–– Toward the LHC operationToward the LHC operation



AGASA reports 18% systematic AGASA reports 18% systematic uncertainty in energy uncertainty in energy determination.determination.

10% of systematic is due to 10% of systematic is due to interaction model.interaction model.

Accelerator calibration is Accelerator calibration is necessary.necessary.

Introduction: GZK cut offIntroduction: GZK cut off

Huge experiment (Auger, TA) will solve Huge experiment (Auger, TA) will solve the statistics, but not for interaction the statistics, but not for interaction model.model.

HOWEVERHOWEVER

Different interaction models give different answers forDifferent interaction models give different answers forthe primary cosmic ray energy estimate.the primary cosmic ray energy estimate.

2929thth ICRCICRCPunePune (India)(India)

GZK GZK cutoffcutoff:: 10102020 eVeV

super GZK super GZK eventsevents?!??!?

20% 20% correctioncorrection on on the the

absoluteabsolute energyenergyscale!!!scale!!!



Introduction: cosmic ray Introduction: cosmic ray compositioncomposition

Not only GZKNot only GZK……

Different interaction models leadDifferent interaction models leaddifferent conclusions about thedifferent conclusions about thecomposition of the primary cosmic rayscomposition of the primary cosmic rays..

IRONIRON

PROTON

PROTON

Knapp et al., 2003Knapp et al., 2003EnergyEnergy ((eVeV))

XX max

max

(g/c

m(g

/cm

22 ))



Development of atmospheric Development of atmospheric showersshowers

Calibration of the models at high energy is Calibration of the models at high energy is mandatorymandatory

The The dominantdominant contributioncontribution toto the the energyenergyfluxflux isis in the in the very forward region (very forward region (θθ ≈≈ 0)0)

In this forward region the highest energy In this forward region the highest energy available measurements of available measurements of ππ00 cross section cross section were done by UA7 (were done by UA7 (E=10E=101414 eV, eV, y= 5y= 5÷÷7)7) 2

θlntany −=

SimulationSimulation of of ananatmosphericatmospheric showershower due due toto a 10a 101919 eVeV protonproton..

LHCLHCWe propose to use LHC, the highest energy We propose to use LHC, the highest energy acceleratoraccelerator14 TeV in the center of mass 14 TeV in the center of mass EElablab=10=101717 eVeV (E(Elablab= E= E22

cmcm/2 m/2 mPP))Major LHC detectors (ATLAS, CMS, LHCB) will Major LHC detectors (ATLAS, CMS, LHCB) will measure the particles emitted in the central measure the particles emitted in the central regionregionLHCfLHCf is a tool to calibrate MC code to energy is a tool to calibrate MC code to energy

relevant relevant for CR physics. It will cover the very forward partfor CR physics. It will cover the very forward part



The LHC ringThe LHC ring

27 km ring27 km ring

ATLASATLAS IP1IP1



LHCfLHCf: location and experimental layout: location and experimental layoutINTERACTION POINTINTERACTION POINT

IP1 (ATLAS)IP1 (ATLAS)

Beam lineBeam line

Detector IIDetector IITungstenTungsten

ScintillatorScintillatorSilicon mstripsSilicon mstrips

Detector IDetector ITungstenTungsten

ScintillatorScintillatorScintillatingScintillating fibersfibers

140 m140 m 140 m140 m

DetectorsDetectors shouldshould measuremeasure energyenergy and position of and position of γγfromfrom ππ00 decaysdecays e.m.e.m. calorimeterscalorimeters withwithposition sensitive position sensitive layerslayers

TwoTwo independentindependent detectorsdetectors on on bothboth side of IP1side of IP1RedundancyRedundancyBackground Background rejectionrejection ((especiallyespecially beambeam--gasgas))



LHCfLHCf locationlocationDetectorsDetectors willwill bebe installedinstalled in the TAN in the TAN regionregion, 140 m , 140 m awayaway fromfrom the the Interaction Interaction PointPoint, in front of , in front of luminosityluminosity monitorsmonitors

HereHere the the beambeam pipe pipe splitssplits in 2 separate in 2 separate tubestubes..

ChargedCharged particleparticle are are sweptswept awayaway bybymagnetsmagnets!!!!!!



Detector #1Detector #1

AbsorberAbsorber22 tungsten layers 7mm 22 tungsten layers 7mm ––14 mm thick14 mm thick

(W: X(W: X00 = 3.5mm, R= 3.5mm, RMM = 9mm)= 9mm)

4 pairs of4 pairs of scintillating scintillating fiber layers fiber layers for tracking for tracking purpose (6, 10, 32, 38 purpose (6, 10, 32, 38 r.lr.l.).)

16 16 scintillatorscintillator layers layers (3 mm thick)(3 mm thick)

Trigger and energy Trigger and energy profile measurements

Impact point (Impact point (ηη))2 2 towerstowers 24 cm long 24 cm long stackedstacked verticallyvertically withwith 5 5 mm gapmm gap

LowerLower: 2 cm x 2 cm area: 2 cm x 2 cm area

Upper: 4 cm x 4 cm areaUpper: 4 cm x 4 cm area

EnergyEnergy

profile measurements



ArmArm 11Arm1 Arm1 waswas fullyfully assembledassembled in in JapanJapan in in JulyJuly 2006 (2006 (scintillatorsscintillators+ + fibersfibers + + TungstenTungsten) and ) and fullyfully testedtested at CERN in at CERN in AugustAugust 2006 2006 beambeam testtest



Detector # 2Detector # 2

4 pairs of 4 pairs of silicon silicon microstripmicrostrip layerslayers(6, 12, 30, 42 (6, 12, 30, 42 r.lr.l.) for tracking .) for tracking purpose (X and Y directions)purpose (X and Y directions)

WeWe usedused LHC styleLHC styleelectronicselectronics and and readoutreadout

16 16 scintillatorscintillator layers layers (3 mm thick)(3 mm thick)

Trigger and energy Trigger and energy profile measurementsprofile measurements

AbsorberAbsorber22 tungsten layers 7mm 22 tungsten layers 7mm ––14 mm thick (214 mm thick (2--4 4 r.lr.l.).)(W: X(W: X00 = 3.5mm, R= 3.5mm, RMM = 9mm)= 9mm)

2 2 towerstowers 24 cm long 24 cm long stackedstackedon on theirtheir edgesedges and offset and offset fromfrom one one anotheranotherLowerLower: 2.5 cm x 2.5 cm: 2.5 cm x 2.5 cmUpper: 3.2 cm x 3.2 cmUpper: 3.2 cm x 3.2 cm

EnergyEnergy

Impact pointImpact point ((ηη))



ArmArm 22oo Arm2 Arm2 waswas partiallypartially

assembledassembled in in FlorenceFlorence in in JulyJuly2006 and 2006 and broughtbrought toto CERN CERN forfor the the BeamBeam Test of Test of AugustAugust20062006

oo Arm2 Arm2 waswas fullyfully assembledassembled in in FlorenceFlorence in in AprilApril 20072007



LHCfLHCf Physics performancePhysics performance1.1. Single Single photonphoton spectrumspectrum2.2. ππ00 fullyfully reconstructedreconstructed (1 (1 γγ in in eacheach towertower))

ππ00 reconstructionreconstruction isis anan importantimportant tooltool forfor energyenergycalibrationcalibration ((ππ00 mass mass constraintconstraint))

Basic detector Basic detector requirementsrequirements: : minimum 2 minimum 2 towerstowers ((ππ00 reconstructionreconstruction))SmallestSmallest towertower on the on the beambeam (multiple (multiple hitshits))DimensionDimension of the of the towertower MoliereMoliere radiusradiusMaximumMaximum acceptanceacceptance ((givengiven the LHC the LHC constraintsconstraints))

SimulationSimulation BeamBeam TestTest



Detectable

Detectable eventsevents

140 BeamBeam crossingcrossingangleangle

LHCfLHCf performances: acceptance on performances: acceptance on PPTTγγ--EEγγ planeplane

A A verticalvertical beambeam crossingcrossing angle > 0 angle > 0 willwillincreaseincrease the the acceptanceacceptance of of LHCfLHCf



LHCfLHCf performances: single performances: single γγ geometrical geometrical acceptanceacceptance

Some Some runsruns withwith LHCfLHCf verticallyvertically shiftedshifted few cm few cm willwill allowallow toto cover the cover the wholewhole kinematicalkinematical rangerange



LHCfLHCf performances: performances: γγ shower in Arm #2shower in Arm #2

Fluka based simulation

7 7 µµm for 1.8 TeV m for 1.8 TeV γγ

Position resolution of detectorPosition resolution of detector

500 500 GeVGeV γγ shower shower



LHCfLHCf performancesperformances: : ππ00 mass mass resolutionresolutionArmArm #1#1∆∆E/E=5%E/E=5%200 200 µµm m spatialspatial resolutionresolution

∆∆m/m = 5%m/m = 5%



LHCfLHCf performancesperformances: Monte Carlo : Monte Carlo γγ--rayray energyenergyspectrumspectrum

(5% (5% EnergyEnergy resolutionresolution isis takentaken intointo account)account)

101066 generatedgenerated LHC LHC interactionsinteractions 1 1 Minute exposure@10Minute exposure@102929 cmcm--22ss--11

luminosityluminosityDiscriminationDiscrimination betweenbetween variousvarious

modelsmodelsisis feasiblefeasible

Quantitative Quantitative discriminationdiscriminationwithwith the help of a the help of a properlyproperly defineddefinedχχ22 discriminatingdiscriminatingvariablevariable basedbasedon the on the spectrumspectrumshapeshape((seesee TDR TDR forfordetailsdetails))



LHCfLHCf performances: performances: model dependence of neutron energy model dependence of neutron energy

distributiondistributionOriginalOriginal n n energyenergy 30% 30% energyenergy resolutionresolution



Performances of the Performances of the LHCfLHCf DetectorDetector

SciFi Position ResolutionSciFi Position ResolutionEnergy ResolutionEnergy Resolution

Measured at the SPS Measured at the SPS Beam Test in 2004Beam Test in 2004

IfIf the center of the the center of the neutralneutral fluxflux hitshits LHCfLHCf

<< 1 mm << 1 mm resolution

LHCfLHCf can measure (and can measure (and provide to LHC) the center of provide to LHC) the center of neutral flux from the collisions neutral flux from the collisions resolution



Now the real installation in LHCNow the real installation in LHC……

PrePre--Installation dates have been fixed in Fall 2006Installation dates have been fixed in Fall 2006–– LSS1L (Arm1)LSS1L (Arm1)

•• 8/01/2007 to 26/01/2007 8/01/2007 to 26/01/2007 FINISHED!FINISHED!–– LSS1R (Arm2)LSS1R (Arm2)

•• 23/04/2007 to 11/05/2007 23/04/2007 to 11/05/2007 FINISHED!FINISHED!

Final installation dates are still under discussion

The idea The idea isis thatthat installationinstallation takestakes placeplace in 2 in 2 stepssteps::PrePre--installationinstallationFinal Final installationinstallation

In In betweenbetween the 2 the 2 installationinstallation the the bakingbaking out of the out of the beambeampipe pipe willwill bebe donedone (200 (200 ooCC), so the ), so the detectorsdetectors shouldshould beberemovedremoved

Final installation dates are still under discussion



LHCfLHCf –– InstallationInstallation



Transport and insertion in the TANTransport and insertion in the TAN



LHCfLHCf possible running scenariopossible running scenarioPhasePhase--II–– Parasite running during the early stage of LHC Parasite running during the early stage of LHC

commissioning (end of 2007 commissioning (end of 2007 –– beginning of beginning of 2008)2008)

–– Remove Remove LHCfLHCf when luminosity reaches 10when luminosity reaches 1030 30 cmcm--22ss--11 for radiation reasonfor radiation reason

PhasePhase--IIII–– ReRe--install the detector at the next opportunity of install the detector at the next opportunity of

low luminosity run low luminosity run PhasePhase--IIIIII–– Future extension for pFuture extension for p--A, AA, A--A run with upgraded A run with upgraded

detectors???detectors???



LHCfLHCf: conclusions and plans: conclusions and plansLHCfLHCf approved in June 2006 by the LHCCapproved in June 2006 by the LHCCPhysics performances: Physics performances: –– able to measure able to measure ππ00 mass with mass with ±±5% resolution.5% resolution.–– able to distinguish the models by measurements of able to distinguish the models by measurements of ππ00 and and γγ–– able to distinguish the models by measurements of able to distinguish the models by measurements of nn–– Beam crossing angle Beam crossing angle ≠≠0 and/or vertical shifts of 0 and/or vertical shifts of LHCfLHCf by few cm by few cm

will allow more complete physics measurementswill allow more complete physics measurementsDetectors:Detectors:–– ARM1 and ARM2 fully readyARM1 and ARM2 fully ready–– Performance measured in Test BeamsPerformance measured in Test Beams

Installation well advancedInstallation well advanced–– ARM1 successfully preARM1 successfully pre--installed in January 07installed in January 07–– ARM2 successfully preARM2 successfully pre--installed in Aprilinstalled in April--May 07May 07–– Final installation date under discussionFinal installation date under discussion

Running conditions:Running conditions:–– Three foreseen phasesThree foreseen phases

•• Phase I: low luminosity run during LHC commissioning Phase I: low luminosity run during LHC commissioning •• Phase II: low luminosity runs and possibly Phase II: low luminosity runs and possibly LHCfLHCf dedicated runsdedicated runs•• Phase III: Heavy Ion runs ?Phase III: Heavy Ion runs ?Waitin

gWaitin

g forfor LHC LHC beams

beams!!!!!!



BackBack--up slidesup slides



The TAN and LHCfThe TAN and LHCf

marbleshielding

manipulator

boxes for DAQ electronic

box box ~ (~ (1515××1515××40) cm40) cm33



Transverse projection of detector #1 in the Transverse projection of detector #1 in the TAN slotTAN slot



Transverse projection of detector #2 in the Transverse projection of detector #2 in the TAN slotTAN slot



Fro

nt

Scin

ti

0 100 200 300

010

020

030

040

0

PMT

R74

00

Si tr

acke

r +

HIB

RID

35mm*35mm + 25mm*25mm

Front Front scintillatorscintillator::FixedFixed position position wrtwrt toto TANTAN

SiliconSilicon + + TungstenTungsten + + ScintillatorScintillator::+/+/-- 5 cm 5 cm verticalvertical excursionexcursion

PMTR

7400

PMTR

7400

Front Front scintillatorscintillatorLateralLateral viewview of ARM #2of ARM #2

Si Si TrackerTracker + + HybridHybrid

BeamBeam axisaxis



γγ raterate



ππ00 raterate



QGSJETII: QGSJETII: usedused modelmodelQGSJET: cQGSJET: c22/DOF=107/125/DOF=107/125DPMJET3: cDPMJET3: c22/DOF=224/125/DOF=224/125SYBILL: cSYBILL: c22/DOF=816/125/DOF=816/125

γγ rayray energyenergy spectrumspectrum forfor differentdifferentpositionspositions



e, µ, p beam

Silicon Calorimeter

The CERN test The CERN test beambeam on on AugustAugust 20042004

Before correction After correction

2 mm



Leak CorrectionLeak CorrectionMonte Carlo

Prototype Experiment

MC predicts that the leakage is energy independent!

correction

Distance from Edge

N P

artic

les



Estimate of the backgroundEstimate of the background

beambeam--beam pipebeam pipeE E γγ(signal) > 200 GeV, OK(signal) > 200 GeV, OKbackground background < 1% < 1%

beambeam--gasgasIt depends on the beam conditionIt depends on the beam conditionbackground background < 1% (< 1% (under 10under 10--1010 TorrTorr))

beam halobeam halo--beam pipebeam pipeIt has been newly estimated from the beam loss rateIt has been newly estimated from the beam loss rate

Background Background < 10%< 10% (conservative value)(conservative value)



SPS Beam TestSPS Beam Test

LHCf LHCf DetectorDetector

SiliconSiliconTrackerTracker

Moving TableMoving TableTrigger Trigger ScintillatorScintillator

CERN : SPS T2 H4CERN : SPS T2 H42006 Aug. 28 2006 Aug. 28 –– Sep. 4Sep. 4Incident ParticlesIncident Particles

––ProtonProton 150,350GeV/c150,350GeV/c––Electron 100,200GeV/cElectron 100,200GeV/c––Muon 150GeV/cMuon 150GeV/cSetupSetup

Test was successfulTest was successfulAnalysis is under way forAnalysis is under way for

Energy calibration of the Energy calibration of the calorimeterscalorimeters

Spatial resolution of the Spatial resolution of the tracking systemstracking systems



Effect of Effect of LHCfLHCf on BRAN on BRAN measurementmeasurement

The effect of The effect of LHCfLHCf on BRAN measurements has on BRAN measurements has been studied in the last months by simulationbeen studied in the last months by simulation–– Reduction of shower particles at BRANReduction of shower particles at BRAN–– Position dependence on beam displacementPosition dependence on beam displacement

(question from machine peoples: if we shift by 1 (question from machine peoples: if we shift by 1 mm the real beam, does the center of the mm the real beam, does the center of the measured neutral energy shifts by 1 mm?)measured neutral energy shifts by 1 mm?)

LUMI monitor (BRAN) inside TAN LUMI monitor (BRAN) inside TAN isis beyondbeyond LHCfLHCf ((replacingreplacing 4th 4th coppercopper bar)bar)

LHCfLHCfLumiLumi

Cu Bar / ZDCCu Bar / ZDCIP1IP1

LHCfLHCfLumiLumi

Cu Bar / ZDCCu Bar / ZDC



Arm #1 Arm #2

H.Menjo

Relative change of the reduction factors for BRAN with respect Relative change of the reduction factors for BRAN with respect to the nominal value (center of the beam: nominal one) to the nominal value (center of the beam: nominal one)

BRAN response BRAN response vsvs beam positionbeam position

If the position of beam center stays within a few If the position of beam center stays within a few mm from the beammm from the beam--pipe center, the reduction pipe center, the reduction

factors do not change more than 10%factors do not change more than 10%

1 x 1 cm2

1 x 1 cm2



LHCfLHCf performances: performances: ππ00 geometrical geometrical acceptanceacceptance

ArmArm #1#1

ArmArm #2#2



LHCfLHCf performances: energy spectrum of performances: energy spectrum of ππ00

Typical energy resolution of Typical energy resolution of γγ is 3 % at 1TeVis 3 % at 1TeV



Optimal Optimal LHCfLHCf run conditionsrun conditions

Beam parameters Beam parameters used for used for commissioning are commissioning are good for good for LHCfLHCf!!!!!!

Beam Beam parameterparameter

ValueValue

# of bunches# of bunches ≤≤ 4343

Bunch Bunch separationseparation

> 2 > 2 µµsecsec

Crossing angleCrossing angle 0 0 radrad140 140 µµradrad downwarddownward

Luminosity per Luminosity per bunchbunch

< 2 x 10< 2 x 1028 28 cmcm--22ss--11

LuminosityLuminosity < 0.8 x 10< 0.8 x 1030 30 cmcm--22ss--11

Bunch Bunch intensityintensity

4x104x101010 ppb (ppb (ββ*=18m)*=18m)1x101x101010 ppb (ppb (ββ*= 1m)*= 1m)

( No radiation problem for 10kGy by a “year” operation with this luminosity )



FromFrom R. R. BaileyBailey presentationpresentation at at JanuaryJanuary 2007 TAN workshop 2007 TAN workshop

Stage 1Stage 1

OptimalOptimal conditionsconditions forfor LHCfLHCf runningrunning!!



FromFrom R. R. BaileyBailey presentationpresentation at at JanuaryJanuary 2007 TAN workshop 2007 TAN workshop

lhcf: a lhc detector for astroparticle...

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